pinmux/pinmux_chennai_2018.tex

   1 \documentclass[slidestop]{beamer}
   2 \usepackage{beamerthemesplit}
   3 \usepackage{graphics}
   4 \usepackage{pstricks}
   5
   6 \title{SIMD}
   7 \author{Rishabh Jain}
   8 \author{Luke Kenneth Casson Leighton}
   9
  10
  11 \begin{document}
  12
  13 \frame{
  14    \begin{center}
  15     \huge{Pin Multiplexer}\\
  16     \vspace{32pt}
  17     \Large{Auto-generating documentation, code \\
  18                         and resources for a Pinmux}\\
  19     \vspace{24pt}
  20     \Large{[proposed for] Chennai 9th RISC-V Workshop}\\
  21     \vspace{16pt}
  22     \large{\today}
  23   \end{center}
  24 }
  25
  26
  27 \frame{\frametitle{Credits and Acknowledgements}
  28
  29  \begin{itemize}
  30    \item TODO\vspace{10pt}
  31   \end{itemize}
  32 }
  33
  34
  35 \frame{\frametitle{Glossary}
  36
  37  \begin{itemize}
  38    \item Pin: an I/O pad.  May be driven (input) or may drive (output).
  39    \item FN: term for a single-wire "function", such as UART\_TX,
  40              I2C\_SDA, SDMMC\_D0 etc.  may be an input, output or both
  41                  (bi-directional case: two wires are always allocated, one
  42                   for input to the function and one for output from the function).
  43    \item Input Priority Muxer: a multiplexer that has N selector
  44                  wires and N inputs, where the lowest (or highest) indexed
  45                  "selector" that is enabled results in its corresponding
  46                  input being routed to the output.\vspace{10pt}
  47    \item TODO\vspace{10pt}
  48   \end{itemize}
  49 }
  50
  51
  52 \frame{\frametitle{Muxer cases to handle}
  53
  54  \begin{itemize}
  55    \item Many FN outputs to Many Pins: no problem\\
  56              (weird configuration by end-user, but no damage to ASIC)\vspace{10pt}
  57    \item One Pin to Many FN inputs: no problem\\
  58          (weird configuration by end-user, but no damage to ASIC)\vspace{10pt}
  59    \item Many Pins to One FN input {\bf Priority Mux needed}\\
  60              No priority mux: Pin1 = HI, Pin0 = LO, ASIC is damaged\vspace{10pt}
  61    \item Some FNs (I2C\_SDA, SD\_D0..3) are I/O Buses\\
  62              Bi-directional control of the Pin must be handed to the
  63              FN\vspace{10pt}
  64    \item TODO\vspace{10pt}
  65   \end{itemize}
  66 }
  67
  68
  69 \frame{\frametitle{Standard GPIO 4-way in/out Mux and I/O pad}
  70  \begin{center}
  71   \includegraphics[height=2.5in]{../shakti/m_class/mygpiomux.jpg}\\
  72   {\bf 4-in, 4-out, pullup/down, hysteresis, edge-detection (EINT)}
  73  \end{center}
  74 }
  75
  76
  77 \frame{\frametitle{Register-to-pad "control" settings}
  78  \begin{center}
  79   \includegraphics[height=2.5in]{reg_gpio_cap_ctrl.jpg}\\
  80   {\bf pullup/down, hysteresis, current, edge-detection}
  81  \end{center}
  82 }
  83
  84
  85 \frame{\frametitle{In/Out muxing, direction control}
  86  \begin{center}
  87   \includegraphics[height=2.5in]{reg_gpio_fn_ctrl.jpg}\\
  88   {\bf Note: function can control I/O direction}
  89  \end{center}
  90 }
  91
  92
  93 \frame{\frametitle{Simplified I/O pad Block Diagram}
  94  \begin{center}
  95   \includegraphics[height=2.5in]{reg_gpio_pinblock.jpg}\\
  96   {\bf 3 wires: IN, OUT, OUTEN (also = !INEN) }
  97  \end{center}
  98 }
  99
 100
 101 \frame{\frametitle{Output (and OUTEN) Wiring. 2 pins, 2 GPIO, 2 Fns}
 102  \begin{center}
 103   \includegraphics[height=2.5in]{reg_gpio_out_wiring.jpg}\\
 104   {\bf Reg0 for Pin0, Reg1 for Pin1, Output and OUTEN same mux }
 105  \end{center}
 106 }
 107
 108
 109 \frame{\frametitle{Input Selection and Priority Muxing}
 110  \begin{center}
 111   \includegraphics[height=0.75in]{reg_gpio_comparator.jpg}\\
 112   {\bf Muxer enables input selection}\\
 113   \vspace{10pt}
 114   \includegraphics[height=1.25in]{reg_gpio_in_prioritymux.jpg}\\
 115   {\bf However multiple inputs must be prioritised }
 116  \end{center}
 117 }
 118
 119
 120 \frame{\frametitle{Input Mux Wiring}
 121  \begin{center}
 122   \includegraphics[height=2.5in]{reg_gpio_in_wiring.jpg}\\
 123   {\bf Pin Mux selection vals NOT same as FN selection vals}
 124  \end{center}
 125 }
 126
 127
 128 \frame{\frametitle{Summary}
 129
 130  \begin{itemize}
 131    \item TODO
 132   \end{itemize}
 133 }
 134
 135
 136 \frame{
 137   \begin{center}
 138     {\Huge The end\vspace{20pt}\\
 139                    Thank you\vspace{20pt}\\
 140                    Questions?\vspace{20pt}
 141         }
 142   \end{center}
 143
 144   \begin{itemize}
 145         \item http://libre-riscv.org/shakti/m\_class/pinmux/
 146   \end{itemize}
 147 }
 148
 149
 150 \end{document}